Year	current US$
2000	9.355562725535368
2001	9.525420690654201
2002	10.156503388698805
2003	12.198986339713462
2004	14.561504672023236
2005	15.491821036325696
2006	18.56441726687851
2007	21.915816813584705
2008	21.900629300134185
2009	23.948151805003384
2010	24.607185736546832
2011	29.509535453388327
2012	31.286079365767392
2013	33.31749822155103
2014	34.768880053290545
2015	33.22125997592619
2016	33.58630503272237
2017	33.809661766143
2018	42.111178502277426
2019	39.911183075319
2020	37.296532032896174
2021	37.847696588911795